Products containing antimicrobials are often touted as cleansers and can be found in the antibacterial soaps and solutions used in schools and places of business; they are also crucial ingredients in the antibiotic medications relentlessly prescribed by medical professionals. Concerned scientists, however, have begun to lobby for improved regulations governing the use of these antimicrobials in medicines and cleaning products, arguing that inappropriate reliance on these compounds has contributed to the emergence of strains of drug- and chemical-resistant bacteria. Still, many school and hospital administrators continue to stress the importance of protecting students and patients from bacterial infection. They refer to studies that suggest that antibacterial cleaning and hygiene products are, in fact, not influential in the development of resistant bacteria and are essential for protection against illness-causing microorganisms.

Much of the debate over antimicrobial use has centered on Triclosan, the primary active ingredient in many antibacterial products. Triclosan's ability to control bacterial contamination by targeting the fatty acid synthesis of bacterial cells has made it an attractive addition to cleaning products. The effectiveness of Triclosan as an antibiotic is not a point of dispute; the real controversy involves the potential negative consequences of excessive use of such products. A chief concern for scientists is that over-use of Triclosan will aid in the development of highly resistant strains of bacteria, as has already been observed in the case of drug-resistant tuberculosis. Supporters of extensive antimicrobial use, meanwhile, deny the existence of evidence that links Triclosan to the development of such "supergerms."

Convincing arguments against Triclosan proliferate: the compound has begun to appear in community water supplies, human breast milk, oceans and decade-old sewage. Scientists worry about the long-term ramifications of Triclosan ingestion, particularly because treatment plants have not yet been able to guard against Triclosan contamination in water sources. The most significant support for this cautionary stance comes from a study conducted at the University of Public Health, where it was found that plain soaps--those that lack antimicrobial agents--remove the threat of bacteria just as effectively as the consumer-grade antibacterial varieties. Furthermore, these studies report that using plain soaps allows non-illness-causing bacteria on skin and other surfaces to successfully compete and protect against those bacteria that do cause illness.

According to the passage, existing studies disagree on which of the following conclusions?


(A) The ability of Triclosan to effectively control bacterial contamination.

(B) The contamination of community water supplies by Triclosan.

(C) The influence of Triclosan on the development of drug and chemical-resistant bacteria.

(D) The effectiveness of plain soap in removing the threat of bacteria as effectively as soaps with antimicrobials.

(E) The importance of using antimicrobial products in schools and hospitals.